Surface-property-based methods, recycling

Plastic-Plastic Separation Both dry and wet processes can be used to separate one plastic from another in a recycling operation. The most common wet separation methods are based on differences in density between particles of different plastics [1, 2, 10, 49], Density is a bulk property of the plastic. Unfortunately, many factors beyond polymer type affect density. Plastic particles can also show differences in surface properties. Plastic-plastic separation methods based on surface property differences include triboelectric separation [75] (a dry process) and froth flotation [75] (a wet process). Density-based and surface-property-based methods for separating a stream of mixed plastics are covered in the following sections. 

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